This is the Dudley Observatory Skywatch Line for Wednesday, June 5th, and Thursday, June 6th, Written by Loui Suarato.
The 9% illuminated, waxing crescent Moon follows Mars into the west-northwestern horizon, and sets at 9:50 Wednesday night. The Gemini twins, Castor and Pollux, trail the Moon. Jupiter rises at 8:41 p.m. in the constellation Ophiuchus. Saturn rises two hours later in Sagittarius. At 43 minutes past midnight on Thursday, Jupiter’s moon Europa begins to be eclipsed by the planet. Europa will reappear at 3:43 Thursday morning. If you would like to follow the various transits, eclipses, and occultations of Jupiter’s moons, you can obtain the phone app, Jupiter’s Moons developed by Sky & Telescope. In addition to the various events of the day, the Jupiter’s Moons app also provides a simulated chart of the Galilean moons’ movements over time. A transit occurs when one or more of the Galilean moons, or their shadows cross between the planet and Earth’s point of view. A Jupiter moon is eclipsed when passes through the planet’s shadow, temporarily obscuring it. Jupiter’s Moons can also be hidden by other Moon’s shadows. An occultation occurs when one object is covered by another. Most occultations result from Jupiter moving in front of its moon, seen from Earth.
June 5 is the 200th anniversary of the birthdate of astronomer John Couch Adams. Born in the United Kingdom in 1819, Adams was famous for predicting the existence and location of Neptune. Adams’ coordinates, and those made independently by Urbain Le Verrier, were sent to Johann Gottfried Galle, who made the visual discovery at the Berlin Observatory. These nights, Neptune can be found between the constellations Pisces and Aquarius, rising after 2 am. Adams also correctly determined that the orbits of a comet and the Leonid meteor shower were similar and, therefore, connected. The comet would later be known as Tempel-Tuttle.